What is produced when $Mg$ burns in $CO_2$?

The activity of a radioactive sample is measured as $N_0$ counts per minute at $t = 0$ and $N_0/e$ counts per minute at $t = 5$ minutes. The time (in minutes) at which the activity reduces to half its value is

If $x^2+y^2+z^2 \neq 0, \quad x=c y+b z, \quad y=a z+c x$ and $z=b x+a y$,then $a^2+b^2+c^2+2 a b c$ is equal to

For the oxidation of $0.2 \ M \ FeSO_4$ solution,$0.965 \ A$ current is passed through it for $1 \ hour$. The volume of the solution that is oxidized in $mL$ is:

How many geometrical isomers are possible for the compound shown below?

In a balanced meter bridge,the resistance of the bridge wire is $0.1 \Omega/cm$. An unknown resistance $X$ is connected in the left gap and $6 \Omega$ in the right gap. The null point divides the wire in the ratio $2:3$. Find the current drawn from a battery of $5 \text{ V}$ having negligible internal resistance. (in $A$)